revert r297155 because there's a clang test that depends on InstCombine:

tools/clang/test/CodeGen/zvector.c

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297166 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/InstCombine/InstCombineCasts.cpp b/lib/Transforms/InstCombine/InstCombineCasts.cpp
index a1ac64dda358182a062750f212ed4212bd9f6e42..e60687fa7ad6c66026ca33a7b22eeac8a43d1626 100644 (file)
--- a/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -463,23 +463,6 @@ Instruction *InstCombiner::shrinkBitwiseLogic(TruncInst &Trunc) {
   return BinaryOperator::Create(LogicOp->getOpcode(), NarrowOp0, NarrowC);
 }
 
-/// Try to narrow the width of a splat shuffle. This could be generalized to any
-/// shuffle with a constant operand, but we limit the transform to avoid
-/// creating a shuffle type that targets may not be able to lower effectively.
-static Instruction *shrinkSplatShuffle(TruncInst &Trunc,
-                                       InstCombiner::BuilderTy &Builder) {
-  auto *Shuf = dyn_cast<ShuffleVectorInst>(Trunc.getOperand(0));
-  if (Shuf && Shuf->hasOneUse() && isa<UndefValue>(Shuf->getOperand(1)) &&
-      Shuf->getMask()->getSplatValue()) {
-    // trunc (shuf X, Undef, SplatMask) --> shuf (trunc X), Undef, SplatMask
-    Constant *NarrowUndef = UndefValue::get(Trunc.getType());
-    Value *NarrowOp = Builder.CreateTrunc(Shuf->getOperand(0), Trunc.getType());
-    return new ShuffleVectorInst(NarrowOp, NarrowUndef, Shuf->getMask());
-  }
-
-  return nullptr;
-}
-
 Instruction *InstCombiner::visitTrunc(TruncInst &CI) {
   if (Instruction *Result = commonCastTransforms(CI))
     return Result;
@@ -571,9 +554,6 @@ Instruction *InstCombiner::visitTrunc(TruncInst &CI) {
   if (Instruction *I = shrinkBitwiseLogic(CI))
     return I;
 
-  if (Instruction *I = shrinkSplatShuffle(CI, *Builder))
-    return I;
-
   if (Src->hasOneUse() && isa<IntegerType>(SrcTy) &&
       shouldChangeType(SrcTy, DestTy)) {
     // Transform "trunc (shl X, cst)" -> "shl (trunc X), cst" so long as the

diff --git a/test/Transforms/InstCombine/trunc.ll b/test/Transforms/InstCombine/trunc.ll
index ba72908d3c4cf316303afc28eca4f2a9408d3d10..581e990df0fa4b6b3349a69bbfea3f476e6f5c1a 100644 (file)
--- a/test/Transforms/InstCombine/trunc.ll
+++ b/test/Transforms/InstCombine/trunc.ll
@@ -478,12 +478,13 @@ define <4 x i8> @wide_shuf(<4 x i32> %x) {
   ret <4 x i8> %trunc
 }
 
+; FIXME:
 ; trunc (shuffle X, undef, SplatMask) --> shuffle (trunc X), undef, SplatMask
 
 define <4 x i8> @wide_splat1(<4 x i32> %x) {
 ; CHECK-LABEL: @wide_splat1(
-; CHECK-NEXT:    [[TMP1:%.*]] = trunc <4 x i32> %x to <4 x i8>
-; CHECK-NEXT:    [[TRUNC:%.*]] = shufflevector <4 x i8> [[TMP1]], <4 x i8> undef, <4 x i32> <i32 2, i32 2, i32 2, i32 2>
+; CHECK-NEXT:    [[SHUF:%.*]] = shufflevector <4 x i32> %x, <4 x i32> undef, <4 x i32> <i32 2, i32 2, i32 2, i32 2>
+; CHECK-NEXT:    [[TRUNC:%.*]] = trunc <4 x i32> [[SHUF]] to <4 x i8>
 ; CHECK-NEXT:    ret <4 x i8> [[TRUNC]]
 ;
   %shuf = shufflevector <4 x i32> %x, <4 x i32> undef, <4 x i32> <i32 2, i32 2, i32 2, i32 2>
@@ -491,13 +492,14 @@ define <4 x i8> @wide_splat1(<4 x i32> %x) {
   ret <4 x i8> %trunc
 }
 
+; FIXME:
 ; Test weird types.
 ; trunc (shuffle X, undef, SplatMask) --> shuffle (trunc X), undef, SplatMask
 
 define <3 x i31> @wide_splat2(<3 x i33> %x) {
 ; CHECK-LABEL: @wide_splat2(
-; CHECK-NEXT:    [[TMP1:%.*]] = trunc <3 x i33> %x to <3 x i31>
-; CHECK-NEXT:    [[TRUNC:%.*]] = shufflevector <3 x i31> [[TMP1]], <3 x i31> undef, <3 x i32> <i32 1, i32 1, i32 1>
+; CHECK-NEXT:    [[SHUF:%.*]] = shufflevector <3 x i33> %x, <3 x i33> undef, <3 x i32> <i32 1, i32 1, i32 1>
+; CHECK-NEXT:    [[TRUNC:%.*]] = trunc <3 x i33> [[SHUF]] to <3 x i31>
 ; CHECK-NEXT:    ret <3 x i31> [[TRUNC]]
 ;
   %shuf = shufflevector <3 x i33> %x, <3 x i33> undef, <3 x i32> <i32 1, i32 1, i32 1>